In recent years, considerable progress has been made in understanding the origins and clinical management of large congenital melanocytic nevi (LCMN). New results from genetics, cell biology, epidemiology, and therapeutic research are flanked by enormous efforts made by patient initiatives around the world, spearheaded by groups in the U.S. and European countries. There is enormous potential for synergy between all of these players. The 2011 International Expert Meeting in Tbingen, Germany enabled the exchange of the most up-to-date, sometimes unpublished information from basic biology and clinical medicine among outstanding researchers in the field. This 2013 International Expert Meeting in Marseille, France will foster and enable the coordination of novel, interdisciplinary and international collaborations among participants. The leadership of major U.S. and European LCMN advocacy groups will attend the conference, to further refine the international initiatives established in 2011. These outcomes will continue making important contributions to the improvement of diagnosis and treatment for patients with this disfiguring and potentially life-threatening disease.